Insulating composition and method of producing same.



UNITED STATES ATENT OFFICE.

ADOLF GENTZSGH, OF VIENNA, AUSTRIA-HUNGARY.

INSULATING COMPOSITION AND METHOD OF PRODUCING SAME.

SPECIFICATION forming part of Letters Patent No. 699,383, dated May 6,1902.

Application filed August 30, 1901. Serial No. 73,798- (No specimens.)

ro ing of a plastic or similar composition for insulating electricalarticles or appliances in the application of the same thereto; and insuch connection it relates to the employment of certain definedmaterials and in the mixing 15 or compounding of the same.

Gutta-percha consists, mainly,of a Wax-like body, a product of rubbersap, (rubber or caoutchouc,) and a species of resin, with the additionof oils. Attempts have been made 20 to produce artificial or imitationgutta-percha,

and experiments have demonstrated that only solutions of the componentsof natural guttapercha could be combined, and hence the attempts to makesuch a product have been at- 2' 5 tended with little success. Moreover,it is impossible to melt gum-rubber or caoutchouo without losing all itsvaluable properties, for the reason that it heated in the open it simplyburns, while if heated in a pan or other 30 similar appliance it yieldsan oily substance designated as caoutchouc or rubber-oil, with theattending loss of all the valuable qualities of the rubber completelygone as a result. v

According to my invention, as extended practice has demonstrated, .ifgum-rubber or caoutchouc be mixed with a vegetable wax, such as palm orcarnauba wax, and the mass is subjected to an intimate kneadingoperation while exposed initially to a mild heat, which is thereafterincreased, a product is obtained having all the properties of naturalgutta-percha and in a form or condition especially adapted for formingan efficient and re liable insulating composition for coveringelectrical articles or appliances and, moreover, a composition coveringwhich is not affected by heat of a passing current or by at mospheric orother somewhat similar conditions. Again, a product or insulatingcomposition is obtainedin which a solvent is not re quired for eitherthe gum-rubber or the other ingredients entering into the composition inthe mixing or compounding and kneading of the mass in production of thesame.

Myinvention, stated in general terms, consists of an insulatingcomposition as a covering for electrical articles or appliances and inthe method of producing the same, substantially as hereinafter describedand claimed.

In preparing or compounding myinsulating compositionI have found inpractice that good results are obtained by the employment of thefollowing ingredients, according to the specified formulas, of, first,twenty parts, by weight, of vegetable wax, such as palm or carnauba wax,twenty parts, by weight, of resin (asphaltum, oolophony, or shellac,)ten parts, by weight, of oil, (olive-oil, common or thickened, accordingto the United States patent of A. Gentzsch, No. 538,828, of May 7,1895,) fifty parts, by weight, of gum-rubber, or, second, sixtyparts,'by weight, of vegetable wax (carnauba or palm wax or resin, themelting point of which has been raised according to the method of the A.Gentz'sch United States Patent No. 657,696, of September 11, 1900,) andforty parts, by weight, of gum-rubber. The gum-rubber or caoutchouc andvegetable wax, such as palm or carnauba wax, either with resin,asphaltum, colophony, or shellac and oil, such as olive-oil, mixed orcombined therewith, are kneaded together in a suitablyheatedkneading-machine, the initial heat of the mass therein being a mild oneand during the operation may be increased up to 100 centigrade, more orless.

As is well known,-gum-rubber or caoutchouc in its natural state isstringy and elastic; but by incorporating with it the vegetable wax,such as palm or carnauba wax, by the intimate kneading operationdescribed the elastic, tough, and stringy nature of the rubber isreplaced by a plastic composition which has all the appearances as wellas properties of the natural gutta-percha before the same has beenhardened. The use of resin, colophony, asphaltum, and oils while notessential is deemed, however, preferable, for the reason that saidmaterials are cheaper than palm or carnauba wax. For that reason insteadof using sixty parts of the wax and forty parts of the rubber theproportions hereinbefore given, in which colophony and the other substances mentioned are used with only twenty parts of wax, would bepreferable from the point of cheapness. When oils are employed under thefirst formula herein given, the same should be added to the mass beforethe starting of malaxation, and the kneading operation under eitherformula of treatment of the ingredients entering into the composition iscontinued until samples taken therefrom show reliable uniformity in theresultant product, which can be readily ascertained from tests made ortaken therefrom.

Having thus described the nature and objeet of my invention, what Iclaim as new, and desire to secure by Letters Patent, is*' 1. Aninsulating composition consisting of gum-rubber or eaoutchouc and avegetable Wax kneaded together under a mild heat which is increasedgradually during the kneading operation, substantially as and for thepurposes set forth.

2. An insulating composition, consisting of gum-rubber or caoutchouc andcarnauba-wax combined together, in about the proportions stated, bykneading under the influence of a mild heat, substantially as and forthe purposes set forth.

The method of making an insulating composition, which consists in firstsubjecting gum-rubber or caoutchouc and vegetable wax, to a kneadingoperation under the influenee initially of a mild heat, and in thenincreasing said heat during the kneading operation, to convert said massinto a composition of a plastic nature, substantially as and for thepurposes set forth.

In testimony whereof I have hereunto set my signature in the presence oftwo subscribing witnesses.

ADOLF GENTZSCII.

Witnesses ALVESTO S. HooUE, AUGUST FUGGER.

